The present invention relates to a vehicle sensor, and more particularly to a sensor attachment arrangement for vehicle air induction components.
Various types of air induction components such as air induction manifolds, air filter assemblies and throttle bodies are used in the field of internal combustion engines. Many known air induction components are presently manufactured of a non-metallic material such as nylon to simplify fabrication and reduce weight.
The prevalence of substantially non-metallic air induction components can create difficulties for the installation of sensors such as temperature sensors, manifold absolute pressure (MAP) sensors, mass air flow sensors, potentiometers and the like. Such sensors are commonly threaded directly into apertures in the air induction components. Other sensors include extended tabs which receive threaded fastener that enter the air induction components. However, these common attachment arrangements can create residue stress between the threaded sensor or fastener. During use, the air induction component heats up and the threaded sensor or fastener may tend to relieve the residual stress by moving away from its installed position. The sensor may then shift away from its original position and cause a degradation of performance.
Another known sensor attachment arrangement includes a barb which snaps onto a ledge. However, the known barb and ledge is relatively easy to disengage. A measure of a snap fit is the locking ratio which can be defined as the force to put the snap-fit in, divided by the force to take the snap fit object out. The locking ratio for the known barb arrangement is approximately 1:2. That is, it requires approximately twice as much force to remove the barb as to insert it. Such a low locking retention ratio is disadvantageous when located adjacent a high-vibration vehicle component.
Known sensor attachment arrangements are also typically unique for each particular sensor. The unique attachment arrangements complicate manufacture of the air induction component and increases the difficulties of substituting sensors for different vehicle and engine types.
Accordingly, it is desirable to provide a sensor assembly which can be easily, securely and inexpensively attached to a non-metallic air induction component without the introduction of residual stress. It is further desirable to provide a generic attachment arrangement to simplify manufacture of the air induction component and allow the interchangeability of sensors.
The present invention provides a vehicle sensor assembly for use in a vehicle gas directing component such as an air intake manifold. The sensor assembly includes a sensor body having a plurality of engagement members which lock the sensor assembly into a sensor receipt member.
The sensor receipt member extends from an external wall of the gas directing component and provides an aperture into the interior of the gas directing component. To engage the sensor assembly, extensions protrude from the sensor receipt member which includes a slot which receives the engagement members.
Each of the engagement members of the sensor assembly define a secondary axis displaced from a primary axis defined along the sensor body. The engagement members each include a first segment which is receivable within a corresponding slot and an enlarged segment which is preferably sized greater than the slot. In one disclosed embodiment, the engagement member is substantially spherical in shape, however, other configurations are contemplated within the present invention.
To install the sensor assembly, a locating segment of the sensor assembly is initially inserted within the sensor receiving member aperture. The sensor assembly is then pressed into the aperture until the enlarged segment of each engagement member encounters an associated extension. By providing additional force on the sensor assembly contact between the enlarged segment of each engagement member forces the engagement members to spread outward from their normal position along their secondary axis. Further force allows the enlarged segments to pass completely by the extensions such that the first segment snaps into the slots and locks the sensor assembly into the installed position. Because the enlarged segment preferably cannot fit through the slot, great force is required to remove the sensor assembly. Thus, although no tools and only a minimum of force is required to install the sensor assembly, much greater force is required to remove it.
In one disclosed embodiment, additional alignment and anti-rotation features can be incorporated into the sensor assembly. Preferably, a slot located within the aperture receives a corresponding tab on the sensor assembly. By maintaining the tab within the slot, the sensor assembly is provided with an anti-rotation retention capability that does not rely entirely upon the engagement members.
In another disclosed embodiment, other installation features such as a radial flange extends from the locating segment. The flange assists in the installation of the sensor assembly by preventing the sensor assembly from being forced too deep into the aperture and is further available to axially compress a seal between the flange and a face of the sensor receipt member.
Another alternate embodiment of an engagement member includes a substantially cylindrical enlarged segment. Yet another disclosed embodiment provides a substantially airfoil appearing shape enlarged segment which engages with an extension as described above. A chamfered edge on the extension may be further adjusted to alter the engagement force.
Still another embodiment provides a sensor assembly removal feature. In this embodiment the extensions include a slot having one ramp-shaped side. By providing each slot with a ramped side, the sensor assembly can be twisted in the direction of the ramp-shaped side to disengage the engagement members from the extensions. Such an arrangement is particularly advantageous in recessed or difficult to reach locations.